When I got into the car at 9am that morning, I was in a good mood; I had been looking forward to the trip. I was going to a relative's wedding in Wales and was stopping off in Bristol on the way, to break the journey with my niece.

The prospect of the 175-mile drive from my home in Ashford in Kent to Bristol didn't faze me. I have been driving for 50 years and am very comfortable behind the wheel, driving happily for long distances and in central London. I had done that journey numerous times before, over the years, visiting my brother and sister-in-law, so I didn't need to consult the map.

Everything was going well until I hit the M25. I took the wrong turning off it, on to the M3 instead of the M4. I knew instantly what I had done, but I didn't panic – I'm not much of a panicker. I just carried on motoring, enjoying the ride. I simply thought that it would add to the fun and I didn't anticipate the calamity that was to come.

After stopping for a cup of tea, I pulled out of the service station, intending to head back to Bristol. Unfortunately, instead of aiming for the northbound carriageway, I drove back the way I'd come, so I was going north on the southbound side of a dual carriageway. I think I had forgotten for a moment that it was a dual carriageway but I realised soon enough when I saw cars heading directly for me.

It was time to take evasive action, so I drove up a slip road on to the M3. This wasn't a good decision as, yet again, I was on the wrong side of the road, and this time it was a motorway.

I kept calm – after bringing up six children, it takes a lot to get me agitated – and decided to steer towards the fast lane, hoping for a gap in the central reservation so that I could get on to the right side of the road. I definitely remember there occasionally being gaps in the central barrier on dual carriageways and I hoped that this was also the case on motorways.

I crawled along at a snail's pace, with the offside wheels of my Nissan Micra up on the kerb. According to the police report, I carried on this way for seven miles, but I honestly don't remember it being more than a few hundred yards. Apparently cars had been swerving to avoid me and beeping their horns, but I remember only one car passing me. Luckily the road wasn't very busy – I know I could have been in a nasty accident if someone hadn't seen me.

A police car drove up alongside and indicated that I needed to pull over. When we were on the hard shoulder, the police officer asked why I hadn't turned round when I'd realised my mistake, and I explained what I'd been trying to do. He was very nice and drove me to a Travelodge where I spent the night before my son picked me up the next morning to drive me home.

I was sad that I'd missed the wedding – I'd been on the road for 19 hours – but otherwise fine. I never realised how much aggravation was to come, until a letter arrived with a court date at Folkestone magistrates court.

In court I was banned from driving for 15 months and fined £200. The magistrate also told me that I would have to retake my test before I could drive again. Who knows how I'll be in over a year's time. I may not be well enough to drive anyway, but if I am, I am sure I would pass my test. I passed first time when I took it in 1961, aged 30. I had to learn in a hurry as my husband died and I needed to ferry my children around.

On reflection, even though I'll miss it, I have decided not to drive again when the ban is lifted. Perhaps what happened was a warning; I know my family would prefer me not to start driving again. I've sold my car and now rely on my mobility scooter for shorter journeys and friends for lifts. I've got another family party coming up in Southend and a relative is taking me. After 50 years in the driving seat, I've accepted that it's my turn to be the passenger.